HARARE, Jan 3 (Reuters) - Zimbabwe plans to import 150,000 tonnes of maize from its neighbour South Africa as it faces its worst food shortages in four years due to drought and a poor harvest last year, state media reported on Friday.

The U.N. World Food Programme has since October been working with the government and international aid organisations to provide food assistance to about a fifth of Zimbabwe's 13 million people until the next crop harvest in March/April 2014.

The South African imports will add to another 150,000 tonnes ordered from Zambia, deputy agriculture minister David Marapira told the government-controlled Herald newspaper. He was not immediately available for comment on Friday.

Marapira told the paper Zimbabwe only had 30,000 tonnes of maize in its strategic grain reserve. The country requires about 2 million tonnes annually.

The southern African state has grappled with perennial seed and fertiliser shortages, with bad weather now worsening the situation.

President Robert Mugabe, re-elected last July in an election rejected as a fraud by his main rival, told a conference of his ZANU-PF party last month that some children had dropped out of school in rural Zimbabwe due to hunger.